Intro to CommunicationPowerPoint PresentationSlide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14Slide 15Slide 16Slide 17Slide 18Slide 19Slide 20Slide 21Slide 22Slide 23Slide 24Slide 25Slide 26Slide 27Slide 28Slide 29Slide 30Slide 31Slide 32Slide 33Slide 34Slide 35Slide 36Slide 37Slide 38Slide 39Slide 40Slide 41Intro to Communicationcs414Karrie KarahaliosWhat is Social Computer Mediated Communication?Signals – brief history Smoke signals, water flows, light Aeneas, 350 BC (first telegraph) First lighthouse, Alexandria 299 BC Sign language, flag signals Chappe audio clock, visual clock Morse Code, 1832Samuel Morse’s message during the first major exhibition of the telegraph: “What hath God wrought”Transcripts from the first transconti-nental telegraph link:“CAN YOU RECEIVE ME?”“PLEASE SAY IF YOU CAN READ THIS.” Telephone, 1876Alexander Graham Bell’s fabled first words over the telephone:“Mr. Watson, come here, I want you.” Arpanet, 1969The ARPANET Completion Report, as published jointly by BBN of Cambridge, Mass., and ARPA concludes by stating: "...it is somewhat fitting to end on the note that the ARPANET program has had a strong and direct feedback into the support and strength of computer science, from which the network itself sprung." (Chapter III, pg.132, Section 2.3.4)Others have understood the communications promise of computers. For example, in RFC 1336, David Clark is quoted, "It is not proper to think of networks as connecting computers. Rather, they connect people using computers to mediate. The great success of the internet is not technical, but in human impact. Electronic mail may not be a wonderful advance in Computer Science, but it is a whole new way for people to communicate. The continued growth of the Internet is a technical challenge to all of us, but we must never loose sight of where we came from, the great change we have worked on the larger computer community, and the great potential we have for future change."In order to develop this network of varied computers, two main problems had to be solved: " 1. To construct a 'subnetwork' consisting of telephone circuits and switching nodes whose reliability, delay characteristics, capacity, and cost would facilitate resource sharing among computers on the network. 2. To understand , design, and implement the protocols and procedures within the operating systems of each connected computer, in order to allow the use of the new subnetwork by the computers in sharing resources." (ARPA not draft, II-8) From http://www.dei.isep.ipp.pt/~acc/docs/arpa--1.htmlArpanet contract was awarded to BBN on 7 April 1969.BBN's proposal called for the network to be composed of small computers known as Interface Message Processors (more commonly known as IMPs). The IMPs at each site performed store-and-forward packet switching functions, and were connected to each other using modems connected to leased lines (initially running at 50 kbit/second). Host computers connected to the IMPs via custom bit-serial interfaces to connect to ARPANET.Leonard Kleinrock and the first IMP. A ruggedized version of Honeywell's DDP-516 computer was used to build the first-generation IMP. The 516 was originally configured with 24 kbytes of core memory (expandable) and a 16 channel Direct Multiplex Control (DMC) direct memory access control unit. Custom interfaces were used to connect, via the DMC, to each of the hosts and modems. In addition tothe lamps on the front panel of the 516 there was also a special set of 24 indicator lights to show the status of the IMP communication channels. Each IMP could support up to four local hosts and could communicate with up to six remote IMPs over leased lines.Initial Arpanet consisted of 4 links:• UCLA• SRI• UCSB• University of Utah (Graphics Dept.)The first ARPANET link was established on October 29, 1969, between the IMP at UCLA and the IMP at SRI. By December 5, 1969, the entire 4-node network was connected. (from wikipedia)This first set of host protocols included a remote login for interactive use (telnet), and a way to copy files between remote hosts (FTP). Crocker writes: "In particular, only asymmetric, user-server relationships were supported. In December 1969, we met with Larry Roberts in Utah, [and he] made it abundantly clear that our first step was not big enough, and we went back to the drawing board. Over the next few months we designed a symmetric host-host protocol, and we defined an abstract implementation of the protocol known as the Network Control Program. ("NCP" later came to be used as the name for the protocol, but it originally meant the program within the operating system that managed connections. The protocol itself was known blandly only as the host-host protocol.) Along with the basic host-host protocol, we also envisioned a hierarchy of protocols, with Telnet, FTP and some splinter protocols as the first examples. If we had only consulted the ancient mystics, we would have seen immediately that seven layers were required." (RFC 1000, pg 4)Network Applications• E-mail: In 1971, Ray Tomlinson of BBN sent the first network email [3]. By 1973, 75% of the ARPANET traffic was email.• File transfer: By 1973, the File Transfer Protocol (FTP) specification had been defined and implemented, enabling file transfers over the ARPANET.• Voice traffic: A Network Voice Protocol (NVP) specifications was also defined (RFC 741) and then implemented, but conference calls over the ARPANET never worked well, for technical reasons; packet voice would not become a workable reality for several decades.1970Arpanet reached east coast (BBN)June 1970 9 IMPSDecember 1970 12 IMPSSeptember 1971 18 IMPS23 hostsAugust 1972 29 IMPSSeptember 1973 40 IMPSJune 1974 46 IMPSJuly 1975 57 IMPS1981213 hostsIn July 1975, the network turned over to Defense Communications AgencyPlato• PLATO pioneered key concepts such as online forums and message boards, online testing, email, chat rooms, picture languages, instant messaging, remote screen sharing, and multiplayer online games.•The name PLATO was chosen for its connection to teaching and only later on did it become a backronym. It was said that PLATO stood for Programmed Logic for Automated Teaching Operations but this was later disavowed and PLATO, despite usually being spelled in all caps, officially stood for nothing.Communication
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